Charak Samhita
भक्षयेद्दन्तपवनं दन्तमांसान्यबाधयन्। निहन्ति गन्धं वैरस्यं जिह्वादन्तास्यजं मलम् ॥७२॥
॥ Oral hygiene: Method of cleaning teeth, tongue and directions for tooth brush use॥ One should clean the teeth with a green twig having a crushed end and of astringent, pungent or bitter taste, twice a day without injuring the gums.
english translation
bhakSayeddantapavanaM dantamAMsAnyabAdhayan। nihanti gandhaM vairasyaM jihvAdantAsyajaM malam ॥72॥
hk transliteration by Sanscript